Tag: commandline

The rib example for the OSL section below comes from a question by rheiland on the Pixar forum https://renderman.pixar.com/forum/showthread.php?s=&threadid=35595 Thank you, it’s a really simple and helpful example.

Then compile it from the commandline using the the following command..

oslc Primvar.osl

Copy the resulting Primvar.oso file into the same directory as your rib file, adjust the comments in there are try again. You should get the same image, you’ve just done it using your own OSL code which you can modify to do other things.

The command line (or unix shell) seems like one of the most archaic way possible to interact with a computer file-system. However most animation and vfx studios require that artists know the basics of interacting with the command line.

There are different types of command lines available, two of the more common are bash and tcsh.

Setting up the tcsh prompt

I primarily use tcsh, so I’ll start with setting it up so it’s more user-friendly. When you start using the default command line, it normally looks pretty dull…

I have my shell setup like so…

It contains a bit more information. It contains my username (will), hostname (will-A8HE), the time and date as well as what directory I’m currently in. I’ve also put the prompt (>) on a new line, this gives me more real estate when dealing with long paths or filenames.

You can control this behaviour by setting up a .cshrc file (also sometimes called .mycshrc). This is a text file which stores information about how you want your shell setup. The first part of my .cshrc looks like this…

# Colors! This makes it easier to edit the colours on the prompt.
set red="%{\033[1;31m%}"
set green="%{\033[0;32m%}"
set yellow="%{\033[1;33m%}"
set blue="%{\033[1;34m%}"
set magenta="%{\033[1;35m%}"
set cyan="%{\033[1;36m%}"
set white="%{\033[0;37m%}"
set end="%{\033[0m%}" # This is needed at the end... 🙁
set prompt="\n%B${green}`whoami`@`hostname`${white}%b %P %D/%W/%y ${blue}%// \n ${white}> ${end}"
# Clean up after ourselves...
unset red green yellow blue magenta cyan yellow white end

This sets up the prompt and because it’s quite awkward setting up colours, we’ve set some variables to make things easier. The hash (#) is used to add comments to the .cshrc file and get ignored by the shell.

The set prompt line can be broken down as follows..

\n Start a newline.

%B Make the text bold.

${green} Make the text green.

`whoami` List my username.

`hostname` List my hostname (computer name).

${white} Make the text white.

%b Make the text not-bold.

%P Time in 24 hour format.

%D Date.

%W Month.

%y Year.

${blue}

%/ The current working directory.

\n Start a newline.

${white} Make the text white.

${end} End colour.

For a more complete listing of all the ways you can modify the prompt, see this page. Next up a few variables to set how the prompt behaves.

set filec
set autolist set color set colorcat
set nobeep

The first of these (filec) enables filename completion, the second (autolist) lists possible options for filename completion and the third (nobeep) stops the command line beeping at you. If you start typing the name of a file and press tab it either completes the name of the file or lists what options you have available. For example if there is only one file in the current directory which starts with ‘a’ and you press ‘a’ then ‘tab’, it will complete the filename for you – saving you from typing. If you have two filenames starting with ‘a’ like ‘andy’ and ‘andrew’ it will complete ‘and’ and list both filenames, press ‘y’ and ‘tab’ and it’ll complete ‘andy’, press ‘r’ and ‘tab’ and it will complete ‘andrew’.

Aliases

The alias command is a command which can be used to setup custom commands. For example I often setup up commands like ‘myren’ or ‘myscripts’ to quickly jump to my render folders or mel/python scripts folder.

The first two list the contents of the directory, (ll) lists them in alphabetical order, (lr) lists them in descending time with the most recently modified file at the bottom. (duho) reports back the disk-usage of the current directory. (resource) is used to restart the shell to pick up any changes or new aliases I’ve added. (remwhite) removes whitespaces from any file names in the current directory. (copy) is similar to (cp) in that it’s used to copy files from one place to the other, however rsync gives you a progress meter so you know how long the file is going to take. (mydev) changes the directory to my local Develop directory, while (myren) relies on an environment variable called $PROJECT and $SHOT to be set, this allows me to change to the correct render folder depending on what project and shot I happen to be working on.

Most studios have their own environment variables setup, so you can normally reference those by using the (env) command in the shell to list all the environment variables available. To set up environment variables you can use (setenv), how the env variables are stored is dependant on where you set them. In my .cshrc I have these setup to affect any shell I open.

APT (Advanced Packaging Tool) is a collection of tools to install and manage software packages on Debian and it’s various off shoots (for example Knoppix and Ubuntu). Much like installing software on other operating systems, a package can contain multiple executables (programs).

In order to install these packages, these are the typical steps that one needs to go through.

Note that APT requires superuser (administrator) privileges which means you have to prefix the sudo command in front of the command. It’s likely if your an artist in a large CG studio that you won’t be a superuser, so these instructions only really apply if your wanting to setup linux at home or in a small studio environment.

The first thing you need to do is get an up-to-date list of all the available packages from the internet.

> sudo apt-get update

The next step is to search for the name of the packages your interested in. APT allows you to do simple word searches for packages

> sudo apt-cache search [package]

Once you’ve found the package your after…

> sudo apt-get install [package]
ie... sudo apt-get install openexr

If the package exists it will download and install the package on your computer, ready to go – no need to restart the computer. Although sometimes you may need to open a new shell in order to pick up any changes. Once that’s done you can upgrade any existing packages on your system by using…

> sudo apt-get upgrade

As an illustrated example, to install the openexr commands you’d run the following series of commands…